scholarly journals Mortality in Forested Ecosystems: Suggested Conceptual Advances

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 572
Author(s):  
Mark E. Harmon ◽  
David M. Bell
Keyword(s):  
Forest Management ◽  
Large Scale ◽  
Tree Mortality ◽  
Structure And Function ◽  
Ecosystem Structure ◽  
General Process ◽  
A Chain ◽  
And Function ◽  
Forested Ecosystems ◽  
Ecosystem Structure And Function

Mortality of trees is an important ecological process altering forest structure and function as well as influencing forest management decisions. Recent observations suggest that the overall rate of tree mortality is increasing at local to global scales. While more data on mortality is needed to document these changes, key concepts are also needed to guide the collection, interpretation, and use of this information. Mortality can be considered as a general process that includes all forms of tree-related death ranging from parts of trees to large-scale disturbances. Viewing mortality as a continuum allows one to examine how the lifespan of trees and their parts (e.g., branches), as well as multiple disturbances, influence ecosystem structure and function. Statistically, mortality does not follow the law of large numbers because, regardless of the scale analyzed, consequential, infrequent episodes can occur. This causes mortality to occur in irregular pulses. While the causes of mortality are indeed complex, this stems from the fact many processes, each with its own set of controls, can lead to mortality. By analyzing and predicting mortality using a chain of events influenced by specific mechanisms, a clearer understanding of this process should develop, leading to a more science-based and less reactive forest management.

scholarly journals Ecosystem-level effects of large-scale disturbance in kelp forests

2020 ◽  
Vol 656 ◽  
pp. 163-180 ◽  
Author(s):  
KM Norderhaug ◽  
K Filbee-Dexter ◽  
C Freitas ◽  
SR Birkely ◽  
L Christensen ◽  
...  
Keyword(s):  
Large Scale ◽  
Single Species ◽  
Structure And Function ◽  
Trophic Levels ◽  
Kelp Forests ◽  
Ecosystem Structure ◽  
Substantial Impact ◽  
Large Scale Disturbance ◽  
And Function ◽  
Ecosystem Structure And Function

Understanding the effects of ecological disturbances in coastal habitats is crucial and timely as these are anticipated to increase in intensity and frequency in the future due to increasing human pressure. In this study we used directed kelp trawling as a scientific tool to quantify the impacts of broad-scale disturbance on community structure and function. We tested the ecosystem-wide effects of this disturbance in a BACI design using two 15 km2 areas. The disturbance had a substantial impact on the kelp forests in this study, removing 2986 tons of kelp and causing a 26% loss of total kelp canopy at trawled stations. This loss created a 67% reduction of epiphytes, an 89% reduction of invertebrates and altered the fish populations living within these habitats. The effect of habitat loss on fish was variable and depended on how the different species used the habitat structure. Our results show that large-scale experimental disturbances on habitat-forming species have ecological consequences that extend beyond the decline of the single species to affect multiple trophic levels of the broader ecosystem. Our findings have relevance for understanding how increasing anthropogenic disturbances, including kelp trawling and increased storm frequency caused by climate change, may alter ecosystem structure and function.

scholarly journals An experimental approach for crown to whole-canopy defoliation in forests

2021 ◽  
Author(s):  
Robert Fahey ◽  
Danielle Tanzer ◽  
Brandon Alveshere ◽  
Jeff W. Atkins ◽  
Christopher M. Gough ◽  
...  
Keyword(s):  
Large Scale ◽  
Ecosystem Structure ◽  
Variable Intensity ◽  
Area Index ◽  
Canopy Volume ◽  
Leaf Level ◽  
Leaf Surface Area ◽  
And Function ◽  
Forested Ecosystems ◽  
Ecosystem Structure And Function

Canopy defoliation is an important source of disturbance in forest ecosystems that has rarely been represented in large-scale manipulation experiments. Scalable crown to canopy level experimental defoliation is needed to disentangle effects of variable intensity, timing, and frequency on forest structure, function, and mortality. We present a novel pressure washing-based defoliation method that can be: implemented at the canopy-scale, throughout the canopy volume, targeted to individual leaves/trees, and completed within a timeframe of hours/days. Pressure washing proved successful at producing consistent leaf-level and whole-canopy defoliation with 10-20% reduction in leaf area index and consistent leaf surface area removal across branches and species. This method allows for stand-scale experimentation on defoliation disturbance in forested ecosystems and has the potential for broad application. Studies utilizing this standardized method could promote mechanistic understanding of defoliation effects on ecosystem structure and function and development of synthetic understanding across forest types, ecoregions, and defoliation sources.

scholarly journals The effects of modern war and military activities on biodiversity and the environment

2015 ◽  
Vol 23 (4) ◽  
pp. 443-460 ◽  
Author(s):  
Michael J. Lawrence ◽  
Holly L.J. Stemberger ◽  
Aaron J. Zolderdo ◽  
Daniel P. Struthers ◽  
Steven J. Cooke
Keyword(s):  
Military Training ◽  
Structure And Function ◽  
Aquatic Systems ◽  
Ecosystem Structure ◽  
Population Declines ◽  
Exclusion Zone ◽  
Negative Effects ◽  
And Function ◽  
Ecosystem Structure And Function ◽  
Modern War

War is an ever-present force that has the potential to alter the biosphere. Here we review the potential consequences of modern war and military activities on ecosystem structure and function. We focus on the effects of direct conflict, nuclear weapons, military training, and military produced contaminants. Overall, the aforementioned activities were found to have overwhelmingly negative effects on ecosystem structure and function. Dramatic habitat alteration, environmental pollution, and disturbance contributed to population declines and biodiversity losses arising from both acute and chronic effects in both terrestrial and aquatic systems. In some instances, even in the face of massive alterations to ecosystem structure, recovery was possible. Interestingly, military activity was beneficial under specific conditions, such as when an exclusion zone was generated that generally resulted in population increases and (or) population recovery; an observation noted in both terrestrial and aquatic systems. Additionally, military technological advances (e.g., GPS technology, drone technology, biotelemetry) have provided conservation scientists with novel tools for research. Because of the challenges associated with conducting research in areas with military activities (e.g., restricted access, hazardous conditions), information pertaining to military impacts on the environment are relatively scarce and are often studied years after military activities have ceased and with no knowledge of baseline conditions. Additional research would help to elucidate the environmental consequences (positive and negative) and thus reveal opportunities for mitigating negative effects while informing the development of optimal strategies for rehabilitation and recovery.

scholarly journals Linking ocean biogeochemical cycles and ecosystem structure and function: results of the complex SWAMCO-4 model

2005 ◽  
Vol 53 (1-2) ◽  
pp. 93-108 ◽  
Author(s):  
Bénédicte Pasquer ◽  
Goulven Laruelle ◽  
Sylvie Becquevort ◽  
Véronique Schoemann ◽  
Hugues Goosse ◽  
...  
Keyword(s):  
Biogeochemical Cycles ◽  
Structure And Function ◽  
Ecosystem Structure ◽  
And Function ◽  
Ecosystem Structure And Function

Impacts of Contaminants and Pesticides on Biodiversity and Ecosystem Structure and Function

2010 ◽  
pp. 111-145
Author(s):  
Thomas Lacher ◽  
"Jr Bickham ◽  
Claude Gascon ◽  
Rhys Green ◽  
Robin Moore ◽  
...  
Keyword(s):  
Structure And Function ◽  
Ecosystem Structure ◽  
And Function ◽  
Ecosystem Structure And Function

Tropical Ecosystem Structure and Function

1974 ◽  
pp. 67-111 ◽  
Author(s):  
Ariel Lugo ◽  
Mark Brinson ◽  
Maximo Cerame Vivas ◽  
Clayton Gist ◽  
Robert Inger ◽  
...  
Keyword(s):  
Structure And Function ◽  
Ecosystem Structure ◽  
Tropical Ecosystem ◽  
And Function ◽  
Ecosystem Structure And Function

Does the severity of non-flow periods influence ecosystem structure and function of temporary streams? A mesocosm study

2018 ◽  
Vol 63 (7) ◽  
pp. 613-625 ◽  
Author(s):  
Isabel Muñoz ◽  
Meritxell Abril ◽  
Joan Pere Casas-Ruiz ◽  
Maria Casellas ◽  
Lluís Gómez-Gener ◽  
...  
Keyword(s):  
Structure And Function ◽  
Ecosystem Structure ◽  
Temporary Streams ◽  
And Function ◽  
Ecosystem Structure And Function
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